Accuracy of three-dimensional printed patient-specific drill guides for treatment of canine humeral intracondylar fissure.

OBJECTIVE To determine the accuracy of three-dimensional printed patient-specific drill guides (3D-PDG) as treatment of humeral intracondylar fissures (HIF) in dogs. STUDY DESIGN Retrospective consecutive case series. ANIMALS Client-owned dogs with HIF treated with a 5-mm transcondylar screw (TCS) placed from medial to lateral with a 3D-PDG. METHODS The proposed TCS entry point and trajectory were planned using computed tomography (CT) data and computer-aided design software (CAD), and a 3D-PDG was produced. During surgery the 3D-PDG was used to drill the pilot hole from medial to lateral; the guide was then removed, the pilot hole was overdrilled, and a 5-mm TCS was placed. Postoperative CT data were imported into CAD software, and the entry points, exit points, and trajectories were compared between the planned and actual screw locations. RESULTS Sixteen elbows from 11 dogs were included. Mean (SD) entry point translation was 1.3 mm (0.64), with all screws entering cranial to the proposed location. Mean maximum screw angulation was 5.2° (2.10°), with most screws directed caudodistal to the desired trajectory. Mean (SD) exit point translation was 1.8 mm (0.89) from the planned location. There was no intra-articular screw placement. CONCLUSION Use of a 3D-PDG permitted accurate placement of a mediolateral 5-mm locking TCS within the humeral condyle. CLINICAL SIGNIFICANCE Three-dimensional printed patient-specific drill guides should be considered as accurate and consistent for placing TCS for treatment of HIF in dogs.